GB/T 16731-2023Classification of sound absorption property for absorbent products using in buildings (English PDF)

Foreword

This document was issued on 17 March 2023 by the State Administration for Market Regulation; Standardization Administration of the PRC and takes effect on 1 October 2023.

It is a GB/T standard: recommended rather than compulsory, but it is the text a Chinese reviewer applies when assessing a submission.

It is classified under ICS 91.120.20, Chinese classification P31.

It replaces GB/T 16731-1997, which is superseded.

This document is in accordance with the provisions of GB/T 1.1-2020 "Guidelines for Standardization Work Part 1. Structure and Drafting Rules for Standardization Documents"

drafting.

This document replaces GB/T 16731-1997 "Classification of Sound Absorption Performance of Building Sound Absorbing Products". Compared with GB/T 16731-1997, except

Apart from structural adjustments and editorial changes, the main technical changes are as follows.

a) The term and calculation method of the weighted sound absorption coefficient are added (see 3.4 and 4.2);

b) Added the terminology and determination method of spectrum characteristics (see 3.5 and 4.3);

c) Changed the sound absorption performance classification parameters of building sound absorption products (see Chapter 6, 4.4 of the.1997 edition);

d) Deleted the detection chapter (see Chapter 5 of the.1997 edition).

This document is modified to adopt ISO 11654.1997 "Sound absorption evaluation of sound-absorbing products for acoustical buildings".

Compared with ISO 11654.1997, this document has more adjustments in structure, and the structure number comparison list between the two documents is shown in the appendix

Record A.

The technical differences between this document and ISO 11654.1997 and their reasons are as follows.

a) Replace ISO 354 with GB/T 20247, which is equivalent to the international standard (see Chapter 1, 5.1);

b) Added the reference to GB/T 3947 (see Chapter 3), which is the terminology of acoustic terms, which can avoid repeated definitions of many acoustic terms;

c) Added the terms and definitions of building sound absorption products, sound absorption coefficient, weighted value, reference value, reference curve, and adverse deviation (see 3.1,

3.2, 3.6~3.9), to express accurately and concisely and conform to Chinese expression;

d) Added a reference to GB/T 8170, and replaced the unclear rounding rules in the original standard with the rounding rules of national standards (see

4.1, 4.2.1);

e) The numerical calculation method of the weighted sound absorption coefficient (see 4.2.1) has been added to adapt to digital development and to provide

convenient;

f) Figure 1 and Figure B.1 in ISO 11654.1997 are deleted, and the ISO standard does not distinguish between reference curves, reference values, and weighted values

points, the expression is not clear, this document adds terms, replaces Figure 1 with Table 1, and replaces Figure B.1 with Table 2;

g) The expression of the weighted sound absorption coefficient alphaw and the low-frequency sound absorption performance (see 5.4) is added to solve the problem that the weighted sound absorption coefficient alphaw does not take into account

Consider the sound absorption performance of the 125Hz octave band;

h) Adjust the content of the informative Appendix B of ISO 11654.1997 to the main text (see Chapter 6) to use the sound absorption performance classification as a specification

sexual element.

The following editorial changes have been made to this document.

a) Change the name of the standard to "Classification of Sound Absorption Performance of Building Sound Absorbing Products";

b) Note 2 is added to the terminology of spectrum characteristic marks, and the symbols of the three marks are explained (see 3.5);

c) The note to 4.1 in ISO 11654.1997 was deleted, and the example was modified according to the numerical rounding rules stipulated in GB/T 8170 (see

4.1);

d) Deleted the note to 5.4 in ISO 11654.1997 (see 5.5), because this note describes the common structural thickness in Europe, Japan and North America;

e) An example of the calculation process of the weighted sound absorption coefficient is added as an informative appendix (see Appendix B);

f) Added a 1/3 octave band sound absorption coefficient alphas result expression chart example as an informative appendix (see Appendix C);

g) Take the original noise reduction coefficient evaluation method as an informative appendix (see Appendix D);

h) References added.

Please note that some contents of this document may refer to patents. The issuing agency of this document assumes no responsibility for identifying patents.

This document is proposed and managed by the Ministry of Housing and Urban-Rural Development of the People's Republic of China.

This document is drafted by. China Academy of Building Research Co., Ltd., Jianke Environmental Energy Technology Co., Ltd., Guangdong Academy of Building Research

Group Co., Ltd., Beijing Academy of Science and Technology Institute of Urban Safety and Environmental Science, Tsinghua University, Chongqing Yushi Technology Co., Ltd.

Company, Beijing Keoke Acoustic Technology Co., Ltd., Huamei Energy Saving Technology Group Co., Ltd., China Energy Saving Technology Group Co., Ltd., China Plan

Quantitative Science Research Institute, Huaqiao University, Tianjin University, Harbin Institute of Technology, Xiamen University, State Grid Hunan Electric Power Co., Ltd., Star Brand Youshiji

Building Materials Co., Ltd., Armstrong Building Products (Suzhou) Co., Ltd., Owens Corning (China) Investment Co., Ltd., Zhengsheng Environmental Division

Technology Co., Ltd., Qingdao Boshi Flame Retardant Fabric Co., Ltd., Beijing Green Creation Acoustic Engineering Co., Ltd., Sichuan Haiyan Acoustic Technology Co., Ltd.

Co., Ltd., Guangxi Dingheng Engineering Quality Inspection Co., Ltd., Guangxi Wanzhong Engineering Inspection Co., Ltd., Beijing Kaibo Wanqian Technology Co., Ltd.

The main drafters of this document. Yan Guojun, Lin Jie, Zhou Quan, Hu Wencheng, Xu Chun, Wu Weibin, Zhao Qiyuan, Zhang Changjia, Xue Xiaoyan, Niu Feng,

Lang Yufu, Ru Lujing, Shen Su, Ou Dayi, Ma Hui, Zhang Juanshu, Wang Bo, Hu Sheng, Gao Tieyan, Zhang Jian, Zhang Zhi, Zhou Jianquan, Zhang Xiaojie, Wang Jiaoyou,

Gong Fenghai, Zhou Yuanbo, Chen Fan, Liu Lizhou, Gao Weimin, Gao Hongquan, Zhang Fenghua, Luo Jia, Kang Jing, Jiang Tao, Liu Qingyun, Wan Ming, Xi Tianyu, Liu Haibin,

Wang Chao, Yao Kun.

This document was first published in.1997, and this is the first revision.

Introduction

This document adopts the weighted sound absorption coefficient alphaw, a new index, to evaluate and classify the sound absorption performance of building sound-absorbing products.

In GB/T 16731-1997, the Noise Reduction Coefficient (NRC) is used as the index value of the sound absorption performance classification of building sound-absorbing products. due to drop

Noise coefficient (NRC) is still widely used at home and abroad, and the noise reduction coefficient (NRC) calculated according to the method stipulated by each country may be used in some cases.

There will be a certain difference. Therefore, in Appendix D of this document, the noise reduction coefficients for evaluating and grading the sound absorption performance of building sound-absorbing products are given.

(NRC) method, which is consistent with the principle of GB/T 16731-1997. The difference is that when calculating the practical sound absorption coefficient alphap, in order to be consistent with this document

The calculation method in the main text is the same, and the calculation results are rounded to 0.5 units with two decimal places according to the method specified in GB/T 8170, and

In the.1997 version, no amendments were mentioned here.

In addition, it should be noted that the noise reduction coefficient (NRC) specified in Appendix D of this document is consistent with the principle of GB/T 16731-1997, and the US

The noise reduction coefficient (NRC) specified in the national standard ASTMC634-13 (2021) is inconsistent. In American standard ASTMC634-13(2021)

In , the specified noise reduction coefficient (NRC) is the average of the sound absorption coefficients of the four 1/3 octave bands of 250Hz, 500Hz, 1000Hz and.2000Hz

Value, rounded to the minimum multiple of 0.05. It is not necessary to calculate the practical sound absorption coefficient alphap first.

Classification of sound-absorbing performance of building sound-absorbing products

1 Scope

GB/T 16731-2023 covers the grading of building sound-absorbing products by how much sound they absorb. It gives the calculation method, the presentation of the result and the classification itself, with informative appendices comparing its structure with ISO 11654:1997, working through a calculation of the weighted sound absorption coefficient (alpha w), and showing how one-third octave band absorption coefficients are charted. It applies to building sound-absorbing products tested to GB/T 20247 that use the sound absorption coefficient as the evaluation parameter. A laboratory measurement yields a curve, an absorption figure in every band, which is exact and of no use to an architect holding three ceiling tiles and a deadline. Reducing that curve to one weighted figure and then to a class is what makes products comparable at the moment they are specified, and it only holds if every laboratory reduces the curve the same way, which is why the calculation and the way the result is presented are fixed here rather than left to the manufacturer. The 1997 edition graded by the noise reduction coefficient, which remains in wide use elsewhere; the weighted coefficient takes its place. For product manufacturers, acoustic laboratories, and the architects and consultants who write absorption into a specification.

This document specifies the calculation method, result expression and sound absorption performance of the weighted sound absorption coefficient used to evaluate the sound absorption performance of building sound-absorbing products.

Grading.

This document is applicable to all architectural sound-absorbing products tested according to GB/T 20247 and using the sound absorption coefficient as an evaluation parameter.

This document does not apply to discrete sound-absorbing bodies that are tested according to GB/T 20247 and use sound absorption as an evaluation parameter, such as seats, space sound absorption

body etc.

The weighted sound absorption coefficient specified in this document can be used in factories, office spaces, schools or hospitals for the purpose of sound absorption and noise reduction.

Evaluate the sound absorption performance of specific building sound-absorbing products or put forward index requirements. But it is not suitable for use in auditoriums, concert halls, theaters and other places to control

To evaluate the sound absorption performance of building sound-absorbing products for the purpose of sound quality or to propose index requirements, in this case, only the complete

The whole sound absorption coefficient data is suitable.

2 Normative references

The contents of the following documents constitute the essential provisions of this document through normative references in the text. Among them, dated references

For documents, only the version corresponding to the date is applicable to this document; for undated reference documents, the latest version (including all amendments) is applicable to

this document.

GB/T 3947 Acoustic Terminology

GB/T 8170 Numerical rounding off rules and expression and determination of limit values

GB/T 20247 Acoustic reverberation chamber sound absorption measurement (GB/T 20247-2006, ISO 354.2003, IDT)

3 Terms and Definitions

The following terms and definitions defined in GB/T 3947 apply to this document.

3.1

Used in buildings, products for absorbing sound energy or sound-absorbing structures composed of sound-absorbing materials, cavities, supporting structures, etc.

3.2

alphas

The ratio of the sound absorption of the test piece to the area of the test piece.

Note 1. The sound absorption coefficient alphas obtained by measuring the reverberation time may be greater than 1.0 (for example, due to the effect of diffraction), so alphas is not expressed as a percentage.

Note 2. The subscript s is to avoid confusion with the sound absorption coefficient defined as the ratio of non-reflected sound energy to incident sound energy, such as a plane wave incident on a plane at a specific angle

The condition of the wall. This "geometric" sound absorption coefficient is always less than 1.0, so it can be expressed as a percentage.

Note 3. The area of the test piece is the area of the ground or wall covered by the test piece. Its source is 3.8 in GB/T 20247-2006.

[Source. GB/T 20247-2006, 3.9, modified]